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Commitb79402a

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WIP revork DtmAdjustOldestXid; it is okay to ignore slot_xmin, but we should wait for long-lived tx
1 parente14e2f9 commitb79402a

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1 file changed

+57
-31
lines changed

1 file changed

+57
-31
lines changed

‎src/backend/access/transam/global_snapshot.c

Lines changed: 57 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -89,15 +89,15 @@ static HTAB *xid2status;
8989
staticHTAB*gtid2xid;
9090
staticDtmNodeState*local;
9191
staticuint64totalSleepInterrupts;
92-
staticintDtmVacuumDelay=10;
92+
staticintDtmVacuumDelay=2;/* sec */
9393
staticboolDtmRecordCommits=0;
9494

9595
DtmCurrentTransdtm_tx;// XXXX: make static
9696

9797
staticSnapshotDtmGetSnapshot(Snapshotsnapshot);
9898
staticTransactionIdDtmGetOldestXmin(Relationrel,intflags);
9999
staticboolDtmXidInMVCCSnapshot(TransactionIdxid,Snapshotsnapshot);
100-
staticTransactionIdDtmAdjustOldestXid(TransactionIdxid);
100+
staticvoidDtmAdjustOldestXid(void);
101101
staticboolDtmDetectGlobalDeadLock(PGPROC*proc);
102102
staticvoidDtmAddSubtransactions(DtmTransStatus*ts,TransactionId*subxids,intnSubxids);
103103
staticcharconst*DtmGetName(void);
@@ -325,47 +325,58 @@ DtmTransactionListInsertAfter(DtmTransStatus * after, DtmTransStatus * ts)
325325
* is older than it more than DtmVacuumDelay.
326326
* If no such XID can be located, then return previously observed oldest XID
327327
*/
328-
staticTransactionId
329-
DtmAdjustOldestXid(TransactionIdxid)
328+
staticvoid
329+
DtmAdjustOldestXid()
330330
{
331-
if (TransactionIdIsValid(xid))
332-
{
333-
DtmTransStatus*ts,
334-
*prev=NULL;
335-
timestamp_tnow=dtm_get_current_time();
336-
timestamp_tcutoff_time=now-DtmVacuumDelay*USEC;
331+
DtmTransStatus*ts,
332+
*prev=NULL;
337333

338-
SpinLockAcquire(&local->lock);
339-
ts= (DtmTransStatus*)hash_search(xid2status,&xid,HASH_FIND,NULL);
340-
if (ts!=NULL)
341-
{
342-
cutoff_time=ts->cid-DtmVacuumDelay*USEC;
334+
timestamp_tcutoff_time=dtm_get_current_time()-DtmVacuumDelay*USEC;
335+
inttotal=0,deleted=0;
343336

344-
for (ts=local->trans_list_head;ts!=NULL&&ts->cid<cutoff_time;prev=ts,ts=ts->next)
345-
{
346-
if (prev!=NULL)
347-
hash_search(xid2status,&prev->xid,HASH_REMOVE,NULL);
348-
}
349-
}
337+
SpinLockAcquire(&local->lock);
338+
339+
for (ts=local->trans_list_head;ts!=NULL;ts=ts->next)
340+
total++;
341+
342+
for (ts=local->trans_list_head;ts!=NULL&&ts->cid<cutoff_time;prev=ts,ts=ts->next)
343+
{
350344
if (prev!=NULL)
351345
{
352-
local->trans_list_head=prev;
353-
local->oldest_xid=xid=prev->xid;
346+
hash_search(xid2status,&prev->xid,HASH_REMOVE,NULL);
347+
deleted++;
354348
}
355-
else
356-
{
357-
xid=local->oldest_xid;
358-
}
359-
SpinLockRelease(&local->lock);
360349
}
361-
returnxid;
350+
351+
if (prev!=NULL)
352+
local->trans_list_head=prev;
353+
354+
if (ts!=NULL)
355+
local->oldest_xid=ts->xid;
356+
else
357+
local->oldest_xid=InvalidTransactionId;
358+
359+
SpinLockRelease(&local->lock);
360+
361+
// elog(LOG, "DtmAdjustOldestXid total=%d, deleted=%d, xid=%d, prev=%p, ts=%p", total, deleted, local->oldest_xid, prev, ts);
362362
}
363363

364364
Snapshot
365365
DtmGetSnapshot(Snapshotsnapshot)
366366
{
367367
snapshot=PgGetSnapshotData(snapshot);
368-
RecentGlobalDataXmin=RecentGlobalXmin=DtmAdjustOldestXid(RecentGlobalDataXmin);
368+
// RecentGlobalDataXmin = RecentGlobalXmin = DtmAdjustOldestXid(RecentGlobalDataXmin);
369+
SpinLockAcquire(&local->lock);
370+
371+
if (TransactionIdIsValid(local->oldest_xid)&&
372+
TransactionIdPrecedes(local->oldest_xid,RecentGlobalXmin))
373+
RecentGlobalXmin=local->oldest_xid;
374+
375+
if (TransactionIdIsValid(local->oldest_xid)&&
376+
TransactionIdPrecedes(local->oldest_xid,RecentGlobalDataXmin))
377+
RecentGlobalDataXmin=local->oldest_xid;
378+
379+
SpinLockRelease(&local->lock);
369380
returnsnapshot;
370381
}
371382

@@ -374,7 +385,16 @@ DtmGetOldestXmin(Relation rel, int flags)
374385
{
375386
TransactionIdxmin=PgGetOldestXmin(rel,flags);
376387

377-
xmin=DtmAdjustOldestXid(xmin);
388+
// xmin = DtmAdjustOldestXid(xmin);
389+
390+
SpinLockAcquire(&local->lock);
391+
392+
if (TransactionIdIsValid(local->oldest_xid)&&
393+
TransactionIdPrecedes(local->oldest_xid,xmin))
394+
xmin=local->oldest_xid;
395+
396+
SpinLockRelease(&local->lock);
397+
378398
returnxmin;
379399
}
380400

@@ -670,6 +690,9 @@ DtmLocalCommitPrepared(DtmCurrentTrans * x)
670690
DTM_TRACE((stderr,"Global transaction %u(%s) is precommitted\n",x->xid,gtid));
671691
}
672692
SpinLockRelease(&local->lock);
693+
694+
DtmAdjustOldestXid();
695+
// elog(LOG, "DtmLocalCommitPrepared %d", x->xid);
673696
}
674697

675698
/*
@@ -717,6 +740,9 @@ DtmLocalCommit(DtmCurrentTrans * x)
717740
DTM_TRACE((stderr,"Local transaction %u is committed at %lu\n",x->xid,x->cid));
718741
}
719742
SpinLockRelease(&local->lock);
743+
744+
DtmAdjustOldestXid();
745+
// elog(LOG, "DtmLocalCommit %d", x->xid);
720746
}
721747

722748
/*

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